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Life in outer space

It may surprise you to realize that this is a question for which we already know the answer: Yes.

Earth is a wonderful example of how life can flourish and abound with astonishing diversity in the midst of the extremely harsh, radiation filled vacuum of space. And this highlights a perception flaw we have when considering life in outer space. We see Earth as distinct and separate from space, but it’s not, Earth is drifting through outer space. Earth is a brilliant example of how life can survive in space.

We live on a modestly sized planet orbiting a rather average star that is currently on the outer spiral arm of an unassuming spiral-barrelled galaxy. Space isn’t something out there somewhere away from us, we are in the depths of space.

Ah, so the question becomes… is there any other life in outer space?

The answer here is almost certainly yes as well, as although we haven’t found life, we have no reason to think that life doesn’t exist elsewhere. We have numerous reasons to think life abounds elsewhere in space. That we haven’t detected life is immaterial, and more a reflection on our inability to examine exo-planets in detail than anything else.

It is a poor sailor who never wants to see beyond the horizon – Plato

As for those who belittle SETI (the Search for Extraterrestrial Intelligence), one has to wonder what they would have said in the days of Christopher Columbus, or about the folly of Charles Darwin setting sail on the HMS Beagle? Exploration defines the quintessential character of humanity, as it is the only catalyst for learning. Whether it be exploring concepts in books or cataloging butterflies in a forest, whether it is a scientist looking for life on Mars or a young child looking for bugs beneath a rock, our curiosity defines us.

Horizons are immaterial. Horizons exist only from the perspective of the viewer. Horizons are an artificial boundary that can be probed and explored, and nowhere is that more true than in the search for life in space.

Astronomy is accelerating in its ability to expand our horizons. For hundreds of years, astronomers and philosophers like Immanuel Kant considered the idea of “island universes,” but it wasn’t until the 20th century that the notion of distinct galaxies emerged. Erwin Hubble took this image of Andromeda (inset) from the Mount Wilson Observatory. While the Hubble Space Telescope has given us this iconic image of Andromeda in astonishing detail and allowed us to view tens of thousands of galaxies stretching billions of years back in time.

The Sloan Digital Sky Survey has mapped almost a million galaxies in a small slither of space, implying that the overall number of galaxies in the visible universe must be somewhere in the hundreds of billions. It is a poor soul indeed that would not want to see this magnificent universe examined in greater detail.

One question that comes up quite often is, “If there is life elsewhere, why haven’t we found evidence for ET?” Seth Shostak in his non-fiction book Confessions of an Alien Hunter, notes that if our galaxy was a haystack then we’re sitting on at least one needle in our solar system. With our efforts so far to examine the stars around us, we have conducted a thorough search of a spoonful of hay and arrived at the conclusion there are no other needles in our sample, but our sample is clearly not representative of the haystack as a whole.

Extending the analogy further, scientists estimate there maybe as many as five hundred billion haystacks to consider, but we can only effectively examine one side of the haystack we’re in. We have no idea how many other needles there may be in our haystack, let alone how many needles there may be in all the other haystacks, but that haystacks have needles is beyond dispute as we’re sitting on one.

When it comes to life in outer space, we’ve got to remember that time is a factor as well.

As Earth cooled, it was subject to the Late Heavy Bombardment with tens of thousands of meteor impacts reaching 12 miles in diameter (20km), roughly forty massive impacts left craters in excess of 600 miles in diameter (1000km), and there were a few whoppers that carved out basins 3000 miles in diameter, that’s roughly the distance from New York to Salt Lake City. And yet, somehow, in the midst of Dante’s inferno, life arose.

What would we have made of Earth if we’d spotted her from afar with the Kepler space telescope at this time? Would we have suspected that the simplest of microbes were already arising amidst this seething hell?

How about this world?

Could this world hold life?

Because as best we understand the evidence, Earth went through several “snowball” periods over the past few billion years. Each of them came perilously close to extinguishing life on Earth.

Our planet is 4.4 billion years old. For at least 3.8 billion years there’s been life on Earth, which is a staggering fact when you stop and consider that the universe itself is only 14+ billion years old. For just under a third of the time the universe has existed, there has been life on Earth! And on Earth, life has endured seemingly insurmountable odds to survive for over 80% of the planet’s history. These are particularly heartening facts when we consider our search for life elsewhere.

We may only have one confirmed example of life in outer space, but it is spectacular in its longevity, its tenacity and its diversity. We have no reason to think the same process hasn’t been replicated elsewhere throughout the universe.

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10 thoughts on “Life in outer space”

yeah, makes it a little more tangible. Seth’s book is really good, going through the history of SETI. They’re covering more and more ground all the time, but the sheer number of star systems to examine is phenomenal, and we’ll only ever be able to examine roughly 60% of our own galaxy as dust in the core blocks light from the far side. As for looking for life in other galaxies, that’s a loooooong way off.

The distances involved are phenomenal, and so just detecting planets is a stretch. At this point, we have no way of detecting life of any kind directly. We could be staring at planets teeming with life and we wouldn’t know it.

Planets are so small relative to their host star, and they only ever reflect an infinitesimally small amount of the host star’s light that seeing them directly is absurdly difficult. It’s like spotting a mosquito buzzing around a spotlight at a baseball game when you’re seated hundreds of yards away.

Most planets are spotted by their “wobble.” Imagine holding hands with a child and swinging them around your body. You’d find it difficult to keep your center of gravity and would “wobble.” Essentially, that’s what we see, the wobbling parent, not the tiny child.

In some cases we can catch a glimpse of light passing through the atmosphere of a planet and get an idea of what the atmosphere is made of, but we can’t learn too much more than that.

A wonderful post, and very well performed. You awaken the research blood thirst in me. Damn it I must go back to watching Carl Sagan’s cosmos, haha!
Have you heard about the recent revelations from FBI about alien life forms?

Hah… no, I hadn’t, but I did find it with a Google search. The problem with aliens visiting Earth and not being detected/popularised is we’re rabid on the subject. It could never stay secret, and if you were a couple of million years ahead technologically (as they presumably are), why would you stay hidden? Just to screw with people’s heads? Ha ha… Oh, makes for great movies, but if aliens ever do come, they won’t bother with cowing to our puny political structures to keep secrets, etc. And they won’t invade. They’ll explore. They’ll be fascinated by our biodiversity. They’d want to understand our evolutionary history. You’ll find them on paleontological digs and cataloguing animals in the rain forests :)

I’m not so sure of that. As to whether it would be known to the general public … well most of us think people who claim to have met aliens are lunatics, so it may be public without us recognizing it. And the aliens may not be scared of us and that may be exactly why they wouldn’t be all that interested in “going public”. I mean, if they didn’t really care about humans or what we do. They might only have apathy left for us. But who knows? It’s hard to decidedly say what they would or would not do. Supposedly the aliens should have crashed, losing their devices, leaving them vulnerable and ready to work with us :P It’s very interesting. I hope it gets debunked or proven while I’m alive.